CEM 141 MSU EXAM 3 COMPREHENSIVE
TEST PAPER 2026 QUESTIONS AND
CORRECT ANSWERS GRADED A+
●● Explain the force and energy changes that occur when two atoms
approach each other and form a bond. Explain why a third body (another
atom or molecule) is (almost always) needed to form a stable bond.
(Think back to what we learned in Chapter 1.
Answer: A third atom will absorb some of the energy thus lowering the
energy between to atoms allowing the two atoms to form a stable bond.
●● What determines whether a bond or interaction is stable? Explain
how temperature influences the stability of bonds and interactions
Answer: The stability of atoms depends on whether or not their outer-
most shell is filled with electrons. If the outer shell is filled, the atom is
stable.
If you put enough energy (heat/temperature) in, the bond will break and
the atoms connected by that bond will fly apart.
●● Compare and contrast the molecular orbital bond model and the
valence bond model. What are the similarities? What are the differences
Answer: ...
●● Valence Bond Theory
, Answer: two orbitals combine to form a bond between two atoms
a single pair of electrons can be shared only by two, bonded atoms in the
molecule
focuses on bonding interactions
uses hybridization to explain geometry of molecules
●● Molecular Orbital Theory
Answer: Orbitals from each atom in the molecule can combine to form
molecular orbitals
a single pair of electrons can be spread across numerous atoms in the
molecule
atomic orbital interactions produce both bonding and antibonding
orbitals
uses symmetry of atomic orbitals to explain geometry of molecules
●● Describe the bonding in diamond and graphite in terms of the hybrid
orbital model (valence bond theory).
TEST PAPER 2026 QUESTIONS AND
CORRECT ANSWERS GRADED A+
●● Explain the force and energy changes that occur when two atoms
approach each other and form a bond. Explain why a third body (another
atom or molecule) is (almost always) needed to form a stable bond.
(Think back to what we learned in Chapter 1.
Answer: A third atom will absorb some of the energy thus lowering the
energy between to atoms allowing the two atoms to form a stable bond.
●● What determines whether a bond or interaction is stable? Explain
how temperature influences the stability of bonds and interactions
Answer: The stability of atoms depends on whether or not their outer-
most shell is filled with electrons. If the outer shell is filled, the atom is
stable.
If you put enough energy (heat/temperature) in, the bond will break and
the atoms connected by that bond will fly apart.
●● Compare and contrast the molecular orbital bond model and the
valence bond model. What are the similarities? What are the differences
Answer: ...
●● Valence Bond Theory
, Answer: two orbitals combine to form a bond between two atoms
a single pair of electrons can be shared only by two, bonded atoms in the
molecule
focuses on bonding interactions
uses hybridization to explain geometry of molecules
●● Molecular Orbital Theory
Answer: Orbitals from each atom in the molecule can combine to form
molecular orbitals
a single pair of electrons can be spread across numerous atoms in the
molecule
atomic orbital interactions produce both bonding and antibonding
orbitals
uses symmetry of atomic orbitals to explain geometry of molecules
●● Describe the bonding in diamond and graphite in terms of the hybrid
orbital model (valence bond theory).
